High Grade B-Cell Lymphoma, NOS
Lessons From the Friday Unknowns
Bone marrow aspirate smears and the touch imprint show numerous neoplastic cells.
The cells are mostly intermediate-size but a small subset are large. Many neoplastic cells have a distinct or prominent nucleolus. The cells have agranular cytoplasm and a subset of these cells has small cytoplasmic vacuoles. A differential count of a bone marrow smear shows 98% lymphoma cells.
The neoplastic cells are positive for CD5 (weak), CD20 (variable and mostly cytoplasmic), PAX-5, MYC (most cells, strong), BCL-2 (strong), MUM1/IRF4 (weak), TdT (5–10% of cells, weak), and IgD, and are negative for CD3, CD10, CD19, CD34, CD138, BCL-6, cyclin D1 and SOX-11.
The neoplastic cells are negative for Epstein-Barr virus encoded RNA.